Agriculture Reference
In-Depth Information
But this leaves us with a problem. Is the Golden bud or pale
green leaf color a Homozygous Dominant (BB) or is it Heterozygous
(Bb).
So now is the time to perform the Test Cross. Any test cross is
a cross of an organism with an unknown dominant genotype (like in
our case) with an organism that is homozygous recessive for that same
trait.
To do this test we need another cannabis plant of the opposite
sex that is homozygous recessive (bb) for the same trait. So we will
stick with bud color as our example. Hey, we have a few silver bud
plants around that we think are recessive. Let's use them and see what
happens. We pollinate the female plant (Does not matter if the female
is dominant or recessive one), and we get our seeds and plant them. 3 -
7 months later we see the results.
This brings us to the next important rule that we will learn.
If any of the offspring from a test cross have the recessive
trait, the genotype of the parent with the dominant trait must be
Heterozygous.
We will explain why in a moment and this will all make
sense to you. Also we must mention that we should be talking about a
large population here. 1000 plants is a good population to be sure with.
100 plants are good but 20 or less can be dodgy.
The more plants we use the more reliable our results will be.
In our example, our unknown genotype is either BB or Bb.
The Silver genotype is bb.
Let's put this information into a mathematical series known as Punnett
